GED Science Physical Science 5

Question 1

Which of the following best describes an endothermic reaction?

Accepted Answer

A reaction that absorbs energy from the surroundings

Answer

Endothermic reactions absorb heat from the surroundings, causing the environment to feel cooler.

Question 2

A student pushes a box across the floor with a force of 30 N and the box moves 4 meters. How much work is done?

Accepted Answer

120 J

Answer

Work = force × distance = 30 N × 4 m = 120 J.

Question 3

What happens to the density of most solids when they are heated?

Accepted Answer

Density decreases because the volume increases while mass stays the same

Answer

Heating causes most solids to expand (increase in volume) while their mass stays constant, so density decreases.

Question 4

Which law states that the total momentum of a closed system remains constant if no external forces act on it?

Accepted Answer

Law of Conservation of Momentum

Answer

The Law of Conservation of Momentum states that total momentum in a closed system is constant in the absence of external forces.

Question 5

A mixture of sand and iron filings can best be separated by using:

Accepted Answer

A magnet

Answer

Iron is magnetic and sand is not, so passing a magnet over the mixture will attract and separate the iron filings.

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